To add a basic tab, you can use the following markup where the root property
is the page you want to load for that tab, tabTitle is the optional text to
display on the tab, and tabIcon is the optional icon.

Sometimes you may want to call a method instead of navigating to a new
page. You can use the (ionSelect) event to call a method on your class when
the tab is selected. Below is an example of presenting a modal from one of
the tabs.